Number of children who were invited and children with German nationality who participated in the study
| Children addressed n | 7498 |
| Questionnaires returned | 85.3% (6399/7498) |
| German children | 87.8% (5629/6399) |
| Blood samples obtained | 59.6% (3356#,¶/5629) |
| Baseline lung function | 65.6% (2313¶/3526+) |
| Blood sample and baseline lung function | 48.8% (1720¶/3526+) |
#: German children only
¶: children with questionnaire returned
+: random subsample, German children only